Hitherto, there has been known a so-called mechanical power splitting (split type or two-motor type) hybrid driving unit, to be mounted to a vehicle, in which an engine, a generator and a driving (assist) electric motor are connected respectively to three elements of a planetary gear, the driving electric motor is coupled with an output shaft, output torque of the above-mentioned planetary gear unit is continuously controlled through control of the generator, and torque of the other driving electric motor is combined with the output torque of the planetary gear to be outputted to the output shaft as necessary.
The hybrid driving unit described above is disclosed, for instance, in Japanese Patent Laid-Open No. Hei. 08-183347 as a unit for an FF (front-engine and front-drive) type vehicle and in Japanese Patent Laid-Open No. 2002-225578 as a unit provided with a transmission between an electric motor and an output shaft.
By the way, the position and direction of the hybrid driving unit to be mounted will totally differ from those of the FF type vehicle in mounting such unit to an FR (front-engine and rear-drive) vehicle.
That is, as for the hybrid driving unit for the FF type vehicle described above, an engine is transversely mounted (so that its crank shaft faces in the transverse direction of the body) and the hybrid driving unit is coupled with one end of the engine so that the longitudinal direction (the direction along its input and output shafts) of a casing member thereof faces to the transverse direction of the body. These engine and hybrid driving unit are stored in an engine room generally provided in the front part of the body. Meanwhile, as for the hybrid driving unit for the FR type vehicle, an engine is mounted longitudinally (so that a crank shaft faces in the longitudinal direction of the body) within an engine room and the hybrid driving unit is mounted to the rear end thereof so that the longitudinal direction of the casing member faces in the longitudinal direction of the body. Therefore, the hybrid driving unit is generally disposed under a compartment between a driver's seat and an assistant driver's seat in the longitudinal direction. Accordingly, concerning to its position, direction and mountability, the hybrid driving unit for the FR-type vehicle is restricted considerably as compared to those of the FF-type. Still more, because the position where it is mounted is close to the compartment as described above, it is strongly desired to reduce its vibration.